Hydraulic steering control apparatus



March 3, 1970 D. SMITH 3,498,060

HYDRAULIC STEERING CONTROL APPARATUS Filed April 10, 1968 2 Sheets-Sheet 1 Men/ran DARCY SMITH United States Patent. .0

US. C]. 60-52 4 Claims ABSTRACT OF THE DISCLOSURE Hydraulic steering control apparatus for craft having a rotatable steering wheel and a steered member wherein a reversible hydraulic pump operated by the wheel is arranged to pump fluid to a reversible hydraulic motor connected to the steered member. The fluid passes through check valves which normally prevent the return flow thereof from the motor to the pump. Check valve operating means operably responsive to fluid pressure in each side of the pump operate the check valves to permit fluid discharge from the motor only when the pump is operated.

BACKGROUND OF THE INVENTION This invention relates to hydraulic steering control apparatus and in particular to steering apparatus for water borne craft such as boats and the like wherein the craft is relatively large size. It is, however, to be understood that the invention may be employed in the guidance system of vehicles other than of the water borne type.

Steering apparatus, particularly boat steering apparatus is normally subjected to heavy strains due to the buffeting action of the water on the rudder and Where the helm is directly connected to the rudder the strains are transferred to the helm and must be overcome by the helmsman who must apply reverse pressure to the wheel.

It is appreciated that hydraulically operated rudder controls have heretofore been devised which have permitted movement of the helm to be transmitted to the rudder which prevent reverse strains imposed upon the rudder from being transmitted to the helm. These controls, however, have, in the main, required the use of valves and the like operated electrically or manually and have therefore been of relatively complicated design which have made them costly to install and diflicult to maintain and operate.

SUMMARY OF THE INVENTION The present invention provides a hydraulic steering control apparatus wherein hydraulic fluid from a presurized source, such as a reversible hydraulic pump manually operated by a steering Wheel or like steering member is fed into a reversible hydraulic motor controlling the movement of a rudder or other steered member through a valve system which normally prevents the return flow of fluid from the motor to the pump. The valve system is provided with mechanical valve operators which are re sponsive to fluid pressure in each side of the pump to open the valves controlling the discharge of fluid from the motor so as to block all movement of the rudder except in the direction dictated by the appropriate movement of the wheel.

The present invention requires no external power for valve operation which consequently results in low manufacturing and maintenance costs. Furthermore, it permits 3,498,060 Patented M ns, 1970 the employment of a plurality of pumps at various stations, each independently operable to control the steered member. The present invention also provides means whereby the entire fluid system may be easily and quickly purged of air.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a diagrammatic representation of the invention as applied to the rudder of a water craft,

FIGURE 2 is central sectional side view of the pump of the invention,

FIGURE 3 is another central sectional side view of the pump of the invention at right angles to the view of FIGURE 2,

FIGURE 4 is a sectional view taken on the line 4-4 of FIGURE 3,

FIGURE 6 is a sectional view taken along line 66 of FIGURE 5,

FIGURE 7 is a sectional view taken along line 7-7 of FIGURE 5,

FIGURE 8 is a sectional view taken along line 8-8 of FIGURE 2, and

FIGURE 9 is a top plan view of the ly in section.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings and in particular to FIG- URE 1 thereof, there is illustrated a reversible, positivetype hydraulic pump 10 operated by a wheel 11 and connected through a valve arrangement 12 and conduits 13 and 14 to opposite sides of a positive-type, reversible hydraulic motor 15, the latter being operably connected to a rudder 17 of a craft to be steered. As illustrated in FIGURE 1, the hydraulic motor 15 is preferably composed of a pair of double-acting hydraulic pistons and cylinder assemblies 19 and 20 having cylinders 21 and 22 and pistons 23 and 24, respectively. Cylinders 21 and 22 are swingably connected at their head ends 26 and 27, respectively to the craft to be steered and the pistons 23 and 24 are connected by piston rods 30 and 31 respectively, to opposite ends of a tiller 33 non-rotatably connected at its middle length to the rudder. Conduits 13 and 14 are connected to the head ends 26 and 27 of cylinders 21 and 22, respectively, and cylinders are interconnected in head to tail relationship by hydraulic pressure conduits 35 and 36.

Distribution means 38 associated with the pump permits the flow of fluid from the pump to the motor 15 through conduit 13 when the wheel 11 is operated in one direction and permits the flow of fluid through conduit 14 when the wheel 11 is operated in the other direction. The valve arrangement 12 is so constructed as to permit the return flow of fluid to the motor through either one of the conduits 13 and 14 when the fluid pressure in the other conduits is increased by appropriate movements of the wheel 11.

Referring now to FIGURES 2 to 9 wherein the pump 10, distribution means 38 and valve arrangement 12 are illustrated in detail, the pump 10, which is shown in the vertical position includes a reservoir 40 having a cylindrical side wall 42 closed at its upper end 43 by an annular cover plate 44 and at its lower end 45 by a base plate 46, both plates being secured as by machine bolts 47.

pump base partial The undersurface 48 of the cover plate 44 is formed as a flat plate sloping in one direction, the dip or slope of said undersurface being indicated by the dash line 49 and rotatably extending centrally through the cover plate is a vertical shaft 50 to the upper end 51 of which the steering wheel 11 is non-rotatably secured.

The base plate 46 is provided with a raised, centrally located, annular shoulder 56 which is surmounted by a centrally located cylindrical boss 57, the latter having a pair of diametrically opposed, circumferentially elongated and circumferentially aligned grooves 58 and 59 formed in its cylindrical surface. These grooves (see FIGURE 8) are in spaced-apart, end to end relationship, one of them lying to one side of a vertical plane extending through the longitudinal axis of the shaft 50 coincident with the dip of the undersurface of the cover plate 44 and the other of the grooves lies on the opposite side of said vertical plane.

Mounted for rotation over the boss '57 is a cylindrical rotor 61 the outside diameter of which is substantially less than the inside diameter of the reservoir so as to form an annular passage 62 therebetween. This rotor is provided with a centrally located downwardly opening cylindrical socket 63 into which the boss 57 rotatably yet slidably fits. The lower end 64 of the rotor 61 slidably and rotatably seats itself on the annular shoulder 56 in spaced-apart relationship to the upper surface 66 of the base plate thereby providing an annular passage 67 extending beneath the rotor and communicating with the annular passage 62. The rotor is also provided with an upwardly opening centrally located bore 71 into which the lower end 72 of the shaft extends, said shaft and rotor being non-rotatably united by means of a conventional key and groove union 73 as illustrated in FIGURE 4.

The rotor is also provided with a plurality (6 being shown) of upwardly opening bores or cylinders 75, said cylinders being arranged in equidistantly spaced-apart relationship with their axes located on a common circle about the axis of the shaft 50. Each of these cylinders has an intake port 76 at its lower end opening into the annular passage 67. Each cylinder is also provided with a check valve 77 over its intake port, each of said check valves comprising a perforated cage 78 holding a ball 79 which is urged by a compression spring 80 against the intake port 76. Each cylinder is also provided with a discharge port 81 opening into the socket 63. These discharge ports are in radial alignment with the grooves 58 and 59 and are a little wider than the space between the adjacent ends of the latter.

Fitted in the cylinders 75 are pistons .85 which are normally urged out of the open upper end of the cylinders by compression springs 86 extending under compression between said pistons and the closed ends of the bores. These springs 86 urge the pistons upwardly against an annular, rotatable wobble plate 87 fitted over the shaft 50. The plate 87 being maintained in rotatable relationship with cover plate by means of a ball type bearing assembly 88 fitted therebetween, located over the shaft. An annular bafile plate 90 having an outside diameter greater than the outside diameter of the rotor 61 is fitted over the annular shoulder 56 and extends through the annular passage 67. This baflle plate is thinner than said annular passage 67 and is provided with a raised portion 92 on its upper surface to maintain it in spaced relationship relative to the lower end of the rotor so as to provide passage for fluid between annular passage 62 and the intake ports 76.

The base plate 46 is provided with a pair of elongated cylindrical distribution chambers 95 and 96 opening at their outer ends 97 and 98, respectively to opposite sides of the base plate, said ends 97 and 98 being sealed by screw type plugs 99 and 100 respectively. At their other ends 101 and 102, respectively, these chambers 95 and 96 terminate in ports 105 and 106, respectively,

4 which form the lower ends of discharge passages 107 and 108, respectively, opening at their upper ends 110 and 111, respectively, into the grooves 58 and 59 respectively. Chambers 95 and 96 are provided with check valves 113 and 114, respectively, check valve 113 comprising a ball 116 urged by a spring 117 against port 105 while check valve 114 has a ball 118 urged by a spring 119 against port 106 Screw threaded passages 122 and 123 extend from the chamber 95 and 96 respectively and open outwardly through the bottom of the base plate. Passage 122 is connected to hydraulic conduit 13 and passage 123 to conduct 14. Extending laterally from distribution chambers 95 and 96 are fluid return passages 125 and 126, respectively, and these return passages 125 and 126 terminate in elongated horizontal cylindrical chambers 128 and 127, respectively, said distribution chambers being formed as elongated bores each opening outwardly of opposite sides of the base plate and being closed by screw type plugs 129 and 130, respectively.

Chamber 127 has a circular orifice at its end opposite plugs 129, said orifice defining one end of a short small diameter passage 136 extending in coaxial relationship with chamber 127, said passage 136 opening at its other end into one end 137 of a cylindrical bore 138, the latter opening outwardly of the base plate at its other end 139 which is plugged by a screw type plug 140. The diameter of the bore 138 is greater than the diameter of the orifice 135. Chamber 127 contains a check valve 141 comprising a ball 142 which is urged against the orifice by a compression spring 143 extending between the plug 129 and the ball 142.

Reciprocally mounted in the bore 138 is a piston 145 having a piston rod 146 extending from one end 147 thereof into and in spaced coaxial relationship with, the passage 136.

A lateral passage 149 extends between the plugged bore 138 and discharge passage 107. A return passage 151 is ported at one end 152 into passage 136 and opens outwardly at its other end 154 through the base plate 46 into the reservoir 40 beneath the bafiie plate 90.

A passage similar to passage 136 terminates at one end in an orifice 161 similar to orifice 135 and at its other end in an elongated bore similar to bore 138 in which a piston 163 similar to piston 145 is located, said piston 163 having a piston rod 164 extending through passage 160 in spaced coaxial relationship therewith. Bore 162 which is closed by a plug 165 communicates with discharge passage 106 through a lateral passage 170.

A check valve 166 similar to check valve 141 is located in chamber 128, said check valve 166 having a check ball 167 spring urged against port 161.

A return passage 169 ported into the reservoir beneath the baflie plate 90 intersects passage 160.

It will be appreciated that the pump 10 is of a type commonly known as a wobble pump and it will be seen that When the rotor 61 is rotated by the wheel 11, the pistons, due to their contact with the wobble plate 87, will consequently pass through a pumping stroke and an intake stroke for each full revolution of the rotor. The check valves 77 permit only one way flow of fluid through the intake ports 76 so that the fluid by each piston 85 as the latter goes through its pumping stroke will be ejected through the discharge port 81 in each cylinder into one of either of the grooves 58 or 59. By rotating the wheel 12 in one direction, fluid will be pumped into groove 58 and conveyed via passage 107 and check valve 113 into conduit 13. When the wheel is operated in the reverse direction the fluid will flow into groove 59 to be conveyed via passage 108 through check valve 114 into conduit 14.

Normally check valves 113 and 166 prevent the return passage of fluid from one side of the motor through conduit 13 while check valves 114 and 141 prevent the return flow of fluid from the other side of the motor via conduit 14. It will be apparent that due to the incompressibility of the hydraulic fluid, no swinging of the rudder will occur under the buffeting action of the water as back pressure applied by the action of the rudder on the motor cannot result in discharge of fluid from the motor. This back pressure cannot, therefore, be transmitted to the wheel 11.

Check valve 141 can only be opened to permit the discharge of fluid through conduit 14 when the wheel is rotated to direct fluid through line 13. Without the assistance of the piston 145 check valve 141 would remain closed when pressure is applied by the pump through line 13. However, hydraulic pressure transmitted through lateral passage 149 to the piston 145 will result in movement of the piston rod 146 against ball 142. The effective pressuregresponsive surfaces of piston 145 and the ball 142 are determined by the respective areas of the bore 138 and orifice 135 and as bore 138 is larger in diameter than orifice 135 the ball 142 can be lifted off the seat when the pressure in bore 138 is less than the pressure in chamber 127. When ball 142 is lifted off the orifice by the rod 146 fluid is then free to flow through line 14 into distribution chamber 96 thence through passage 126 into chamber 127 thence through the orifice 135 into passage 136 and upwardly into the reservoir 40 through the return passage 151. It will be understood that the return flow of fluid through. line 13 will be effected by the operation of the piston 163 on the check valve 166 as described with respect to the return flow of fluid through conduit 14.

During the circulation of the fluid from the pump through the motor and back to the pump, air may at some time enter the line. As the return fluid flows into the reservoir through the relief passages 151 and 169 it is directed radially outwardly by the baifle plate 90 beyond the periphery of the rotor. Any air bubbles carried by fl1e fluid will therefore rise upwardly through the annular passage 62 away from the intake ports 76. Air bubbles will therefore be constantly bled from the system during operation thereof.

It will be further understood that the pump may be operated with a rotor 61 having only one piston 85, however, this will result in an intermittent flow of fluid as the piston alternately moves through its pumping and intake strokes Whereas the provision of an even number of pistons equidistantly spaced apart will result in a smooth uninterrupted flow of fluid. Similarly, the provision of a motor 15 having two double acting piston and cylinder assemblies 19' and 20 having their pistons operably connected to the tiller 33 results in equal and opposite flow of the fluid being discharged from and returning to the pump so that level of fluid in the pump will remain constant. If it is required, therefore, the reservoir 40 can be made airtight by the provision of suitable seals, not shown, between the shaft 50 and cover plate 44. If the reservoir is exposed to atmospheric pressure, one piston and cylinder assembly instead of both assemblies 19 and 20 may be used as the fluid is returned directly to the reservoir.

The design of the pump 10 and its associate valve arrangement 12 and distribution means 38 permits the development of a steering system operable from various stations in the vessel to be steered.

As previously noted, until the Wheel 11 is turned none of the valves will open to permit the flow of fluid into or out of the cylinders 21 and 22. Furthermore, back pressure applied to the pistons 30 and 31 cannot effect rotation of the wheel 11. A plurality of pumps (one being shown in dotted lines in FIGURES 1) which are duplicates of pump 10, and to 'Which duplicate reference numerals have been applied, may be connected to conduits 13 and 14 in parallel with pump 10 and located at strategic stations in the craft. Operation of the wheel 11 of any pump will, without affecting any of the other pumps, thereby effect operation of the piston and cylinder assemblies 19 and 20.

As hereinbefore described, the pump -10 may be used in conjunction with a positive-type, reversible, hydraulic motor such as the piston and cylinder assemblies 19 and 20. It is preferred, however, that it be used in conjunction with a slave cylinder as described in US. Patent No. 3,233,407 entitled, Hydraulic Control Apparatus and Control Valve Therefor. In this patent the slave cylinder which corresponds to either of cylinders 21 and 22 is provided with a piston and piston rod which can, if desired, be so arranged as to permit direct communication between opposite ends of the slave cylinder so that fluid, when injetced into one end thereof, will pass therethrough and exit at the opposite end. This type of cylinder when used in conjunction with pump 10 will permit the entire system to be purged of air in a very short time. When the apparatus is initially installed in a craft, this slave cylinder may be opened to the passage of fluid therethrough when the wheel 11 or wheels 11 if more than one pump is installed, may be rotated back and forth until the fluid has been completely circulated throughout the entire system. Any air entrapped in the fluid will leave the latter when the fluid reaches the reservoirs 40 of any of the pumps, as hereinbefore described. After the air has been purged from the system the piston and piston rod in this slave cylinder may then be rearranged so as to become operative.

I claim:

1. Hydraulic steering control apparatus comprising a casing having a bottom, said casing being adapted to hold hydraulic fluid, a pair of fluid discharge passages opening at one end through the bottom of the casing and being connectable to opposite sides of a reversible hydraulic motor, a reversible wobble pump in the casing having at least one intake port confronting said bottom and being adapted to be operable selectively to direct fluid through either of said discharge passages, a pair of fluid return passages connectable to said opposite sides of said motor and opening into the casing through the bottom thereof, a baffle plate arranged between the pump and bottom of the casing for directing fluid returning through the return passages away from the intake port of the pump, check valves in all of the passages normally preventing the return flow of fluid from the motor to the pump and casing and a check valve operator behind each check valve in each discharge passage operably responsive to fluid pressure therein when the pump is operated to discharge fluid into either side of the motor for opening the check valve in the return passage having a fluid connection to the opposite side of the motor.

2. Hydraulic steering control apparatus as claimed in claim 1 wherein each check valve operator presents an effective pressure responsive surface to the fluid in its associated discharge passage greater than the effective pressure responsive surface of its associated check valve.

3. Hydraulic steering control apparatus as claimed in claim 1 including yieldable means normally urging the check valves to closed positions.

4. Hydraulic steering control apparatus as claimed in claim 1 wherein the wobble pump includes a rotor having a plurality of cylinders mounted for rotation in the casing about a central axis, said cylinders each having a discharge port and an intake port, a fixed Wobble plate connected to the casing above the rotor and tilted at an angle to the rotational axis of the latter, a piston in each cylinder, each piston being operably engaged with the wobble plate so as to be moved by the latter through a pumping stroke and an intake stroke when the rotor is rotated one full revolution, and wherein said one end of each discharge passage is formed as a circumferentially elongated arcuate port, one of said arcuate ports being arranged to receive the fluid discharge from the discharge ports of the cylinders when the rotor is rotated in one direction and the other of said arcuate ports being ar- 7 8 4 range to receive said fluid discharge when the rotor i s 3,233,408 2/1966 Smith 60 52 rotated in the opposite direction. 3,333,416 8/1967 Budzich 18079.'2 XR References Cited FOREIGN PATENTS UNITED STATES PATENTS 5 5 /1955 France.

692,879 2/1902 Lem!) 6052 EDGAR w. GEOGHEGAN, Primary Examiner 1,993,612 3/1935 Lum 6052 2,580,064 12/1951 Albright 18079.2 XR U.S. Cl. X.R.

2,984,985 5/1961 MacMillin 60-52 XR 114-450 

